CHAPTER X 

 THE LYMPHATIC SYSTEM 



THE lymphatic series includes a system of lymphatic chan- 

 nels which collect the lymph from the various tissues of the body 

 and return it to the large veins of the neck, where it mixes with 

 the blood. In the course of this lymph vascular system are various 

 aggregations of lymphoid or adenoid tissue which occur in the 

 form of lymphoid nodules or follicles, lymphatic glands or nodes, 

 and the lymphoid organs. These organs are the tonsils, thymus, 

 and spleen. The lymphatic vessels also stand in intimate relation 

 if not in direct communication with the serous and synovial mem- 

 branes and the bursae. 



LYMPH. Like the blood, the lymph may be considered as a 

 primary tissue whose intercellular elements are entirely of a fluid 

 nature. In most portions of the body, lymph is a colorless fluid 

 which is scantily provided with corpuscular elements, the lym- 

 phatic corpuscles. The lymphatic corpuscles are identical with 

 the leucocytes of the blood. In the lymph most of these cells are 

 of the mononuclear form, the small mononuclears or lymphocytes 

 being the most abundant. Lymph also contains a small propor- 

 tion of polynuclear cells, which not only are derived from the 

 lymphoid tissues, but as wandering cells find their way into the 

 lymphatic vessels from the tissues generally. 



In addition to the leucocytes lymph contains fat globules and 

 glycogen. These are mostly the products of absorption from the 

 intestinal tract, in which process the lymphatic vessels play an 

 important role. In the lymphatic vessels of the intestine during 

 absorption fat globules are so abundant as to impart to the lymph 

 a milky white color ; this variety of lymph is termed the chyle. 

 These fat globules are rapidly removed by the lymphoid organs, 

 since even in the presence of abundant chyle only comparatively 

 few fat globules escape into the general blood current. The 

 lymph of other portions of the body than the abdominal region, 

 therefore, contains relatively little fat. 

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